SPEEK/epoxy resin composite membranes in situ polymerization for direct methanol fell cell usages

Sulfonated poly(ether ether ketone) (SPEEK)/4,4′-diglycidyl(3,3′,5,5′-tetramethylbiphenyl) epoxy resin (TMBP) composite membranes in situ polymerization were prepared for the purpose of improving the methanol resistance and mechanical properties of SPEEK membranes with high ion-exchange capacities (IEC) for the usage in the direct methanol fuel cells (DMFCs). The effects of introduction of TMBP content on the properties of the composite membranes were investigated in detail. The composite membranes have good mechanical, thermal properties, lower swelling ratio, lower water diffusion coefficient (0.87 × 10⁻⁵ cm² s⁻¹ at 80 °C) and better methanol resistance (5.26 × 10⁻⁷ cm² s⁻¹ at 25 °C) than SPEEK membranes. The methanol diffusion coefficients of the composite membranes are much lower than that of SPEEK membrane (17.5 × 10⁻⁷ cm² s⁻¹ at 25 °C). Higher selectivity was been found for the composite membranes in comparison with SPEEK. Therefore, the SPEEK/TMBP composite membranes show a good potential in DMFCs usages.